[BC] Shopping center arrays

[gRAdy Moates]

WWZN (the station that followed the legendary WMEX on
1510 in Boston) is in the middle of an industrial park, and
cars park all around the towers, and within 15 feet of the
reference tower, on asphalt.  We had to do whole-body
averaging every six inches to pass RFR regulations.

199-degree-tall towers, 90 degrees apart, in a rhombus.
50 kW DA-3.  I maintain it.  It's stable.

The array had slowly walked away from the original
parameters over a 20-year period, and was becoming
increasing difficult to keep 'in'.  Parameters had to be
relicensed several times  Then we lost a fiberglass
rod insulator and guy wire, but the tower didn't come down.
Then we lost another fiberglass rod insulator and guy wire,
but the tower _still_ didn't come down.

So we replaced ALL the guy wire assemblies (60 of
them), including all Johnny-ball insulators.

The patterns all went to hell.  After massaging, the
parameters came back to almost exactly what they had
been in 1980, when we built it.  More than 20 of the Johnny-
balls had a spider-web of cracks all the way through them,
with all kinds of black crap inside.  We figured that the
segmenting of the guys had failed due to arc paths through
the insulators.

There are now three ERI sunflowers atop each tower,
in the hope that we won't lose any more Johnny-balls.

So far so good, 2 years down the road.

Grady


----- Original Message ----- 
From: "Gary Peterson" <kzerocx at rapidcity.net>
To: <broadcast at radiolists.net>
Sent: Monday, November 21, 2005 9:05 AM
Subject: [BC] Shopping center arrays


> Is anyone aware of any horror stories involving a public roadway passing
> through a directional array?  I wonder if large parked vehicles or the
> addition of light standards/traffic lights has had any significant effect 
> on
> phase/ratio/monitor point field strengths.
>
> I would assume, if this is a problem, that arrays with higher mutual
> impedances between towers and licensed at higher frequencies would be most
> affected.
>
> Gary, K?CX
> Rapid City, SD
>
> " WGUL 860 site in Safety Harbor Florida (Clearwater area) has their three
> towers in an industrial park.  The streets go under the guys.  One tower 
> is
> in a small parking lot next to one of those steel buildings, another is in
> the middle of a retention pond in the middle of the industrial park.
> I always wonder how hard it is to keep that array in tune
>
> Paul Smith "
>
>
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